Untersuchungen über Protein- und RNA-Synthese in dormanten und nachgereiften Samen von Melandrium noctiflorum

Abstract

Summary In Melandrium noctiflorum seeds germination and the capacity for general protein and RNA syntheses are not directly correlated. Dormant and afterripened seeds of the harvest 1974 do not show any differences in 14 C-alanine and 3 H-uracil incorporation after soaking 12 and more hours under different conditions which can induce (paper factor, red and white light) or inhibit (far-red light, 30°C) germination. However, there are differences in the start of protein and RNA syntheses in dependence of the physiological state of the seeds. RNA, and especially protein syntheses in dormant seeds start earlier than in afterripened ones. When afterripened seeds were brought to a second dormancy by long-time irradiation with far-red, a high level of 14 C-alanine incorporation occurs. Therefore we conclude that bulk protein and RNA syntheses do not control germination of these seeds. Ethylene is partially able to break dormancy of Melandrium noctiflorum seeds, especially in combination with white light, but there is no enhanced incorporation of 14 C-alanine and 3 H-uracil into ethylene treated seeds, too. Nevertheless, there is a rapid inhibition of germination by reducing protein and RNA syntheses after application of the specific inhibitors, cycloheximide and 2-thiouracil. According to these results dormancy of Melandrium noctiflorum seeds seems not to be caused by a general but by a specific metabolic block.